The Moors from North Africa were great castle builders and the fortifications they erected after their invasion of the Iberian peninsula are among the best examples of Moorish Forts anywhere.
While their fortifications in Spain in cities like Seville and Granada are well known, the buildings they left behind in Portugal are less known.
These magnificent castles were gradually conquered by Christian forces as they retook the peninsula after several hundred years of Moslem rule.
The Castle of San Jorge which overlooks Lisbon was taken in 1147, by King Alonso the 1st assisted by British, French and Scandinavian Crusaders, bringing to an end the Seige of Lisbon which had lasted more than four months.
It was an important victory that led to the surrender of Moslem forces twenty miles away in the hilltop town of Sintra in the same year. This incredible hilltop castle had been built by the Moors 350 years earlier on a spot which could oversee the Atlantic Coast and surrounds for miles in all directions.
It was another 40 years before the red sandstone Fortress, at a Silves, two hundred miles to the south in the Algarve, was taken by Sancho the 1st in 1189 after an another seige lasting several months.
Sancho, whose statue stands at the entrance of the fortress, was also assisted by Crusaders en route to battles in the Holyland.
Thirty thousand Moors retreated into the Fortress but thousands were later killed by Crusaders after surrendering .
The Moors retook the Fortress two years later only to to lose it again, finally, to the Christians fifty years later in 1249.